Anode for electron guns



1940- J. R. BEERS 2,212,144

ANODE FOR ELECTRON GUNS Filed July 11, 1958 Patented Aug. 20, 1940 1.1;" NiTED ST E John RrBeers, Bloomfield, Nt Application July '11, msa Qs ris sm z ar o I g y 3 Claims.

This invention relates to an anode for electron guns. The anodecomprises two sheet metal lens electrode elements arranged in a metaltube and spaced apart from one another, as shown on a 5 greatly enlargedscale in the accompanying drawing. Each element comprises a disk havinga peripheral flange fitting closely within the tube and by which it isfrictionally held' in a desired position within the tube, and the diskshave small alined perforations at their centers.

these perforations, which are about the size of a pin hole, are made bya punch which may leave sharp edges or projections at the margins of theperforations, which are objectionable from the electrical standpoint,and sometimes in forcing the elements into their desired positions inthe tube the perforations are thrown out of exact alinement by warpingof the disks.

The object of the present invention is to so form the elements that theforegoing objections will be overcome. In the preferred way of carryingout the invention the punched perforation in the disk is made slightlylarger than the required opening and a small eyelet is inserted. in

the perforation in the disk, and by upsetting the in the tube. Similarresults may be accomplished by drawing the metal of the disk intheprocess of making the central perforation, producing a circularflange which is then upset and flattened against one side of the disk bya suitable upsetting mechanism having a mandrel of the exact diameter ofthe hole which it is desired to produce in the disk, so that when themandrel is withdrawn the hole in the disk will be a true circularopening of the size desired, free from sharp edges or projections, andthe disk will be reinforced at its central portion adjacent. theopening, which will aid in preventing distortion of the disc when it isbeing pressed to its position in the tube.

In the accompanying drawing in which the anode and its lens element areshown on a greatly enlarged scale,

55 Figure 1 is a central longitudinal section Usually of the elementwhen it is pushed into its place through the anode; showing the lenselements with eyelets in the perforations,

FigureZ is a central section through one of the discs with an eyeletfitting into the perforation in the disc, 5

Figure 3 is a similar view showing the eyelet ends flattened against thefaces of the disk around a mandrel of an upsetting tool,

Figure 4 is a central section through one of the discs with theperforation in the disk made 10 by drawing the metal, leaving a circularflange, and

Figure 5 shows the flange flattened against the disk around a mandrel,which, when removed leaves a true circular opening of the exact diam- 15eter desired and with a smooth edge.

Referring to the drawing, Figure 1, A indicates the anode comprising themetal tube a and the spaced lens electrode elements b. Each lenselectrode element comprises a disk I having a 2 peripheral flange 2which fits closely within the tube and holds the disk frictionally inplace. Small central perforations 3, slightly larger than the openingsdesired are made in the disks by a punch, and eyelets 4, inserted in theperfora- 25 tions, are shown with their ends pressed against theopposite sides of the disks. Figure 3 shows an eyelet fitted into theperforation-in one of the disks, and Figure 4 shows the ends of theeyelet flattened around the margin of the opening in 30 the disk, whichis accomplished by applying pressure with a suitable upsetting toolhaving a mandrel 5, the diameter of which is the same as that of thedesired opening to be produced in the lens element, so that when themandrel is withdrawn 35 the opening through the eyelet will be of theexact diameter required and only smooth and rounded surfaces will beexposed to the electron stream passing through the opening. The lens 1element will also be strengthened in its central 40 portion, by theeyelet, so that liability to distortion of the lens element will belessened when force is applied to it in the subsequent handling of thelens element.

In Figures 4 and 5 are illustrated the method 5 of accomplishing thedesired result without the use of the eyelets. In this case, in formingthe central perforation in' the disk In. of the lens element b, themetal is drawn, forming a circular flange 6 which is cut off to make itof suitable length. Then, as shown in Figure 5, a mandrel l, of theexact diameter of the hole desired in the disc, is inserted in theopening 3a and the flange 6 is compressed against the face of the disk,as shown at 6a, leaving an opening of the exact diameter of the mandrel,with smooth and rounded edges, when the mandrel is withdrawn. The lenselement is also strengthened at its central portion by the overturnedmetal 6a which helps to prevent warping of the element in subsequentmanipulation of the same.

What I claim is:

1. An anode for electron guns comprising a metal tube having spaced lenselectrode elements therein, each element comprising athin metal diskfitting closely within the tube and having a central perforation, and aneyelet aifixed to the disk fitting within said perforation and coveringthe edges thereof, the end portions of the eyelet being upsetagainst'the opposite sides of the disc;

2. An anode for electron guns comprising a metal tube having spaced lenselectrode elements therein, each element comprising a thin metal diskfitting closely within the tube and having a central perforation withthe metal of the disk drawn in making the perforation into the form of acircular flange, said flange being upset against the face of the disk,forming an opening through the disk of definite diameter and with smoothsurfaces.

3. An anode for electron guns comprising a metal tube having spaced lenselectrode elements therein, each element comprising a thin metal diskfitting closely Within the tube, said disk having a small centralperforation therethrough, and metal reinforcing means surrounding saidperforation, said reinforcing metal being compressed against one face ofthe disk, whereby an opening of definite size and with smooth surfacesis produced.

JOHN R. BEERS.

